The Zanzibar red colobus (Piliocolobus kirkii) is a species of red colobus monkey endemic to Unguja, the main island of the Zanzibar Archipelago, off the coast of Tanzania. It is also known as Kirk's red colobus after Sir John Kirk, the British Resident of Zanzibar who first brought it to the attention of zoological science. It is now classified as an endangered species and in the mid-1990s was adopted as the flagship species for conservation in Zanzibar. The population is still decreasing, and conservationists are attempting to work with the local government to devise a proper, effective strategy to protect the population and habitat. Challenges include the species' habitat, which is limited to the archipelago. The species has been reclassified three times; it was previously in the genus Colobus, then in the genus Procolobus, and later in the genus Piliocolobus.
Evolutionary history and taxonomy
The Zanzibar red colobus, Piliocolobus kirkii, population on Zanzibar, represents a population of red colobus that is believed to have been isolated on the island after sea levels rose toward the end of the Pleistocene epoch. Furthermore, it is suggested through mitochondrial analysis, that phylogenetic groups within the red colobus have been genetically isolated from another since the Pliocene.
Examining cranial morphology has shown that P. kirkii has diverged from mainland Piliocolobus to its own species. It has experienced an acceleration in morphological evolution of size which is suggested to be the result of insularity on the island and environmental pressures such as competition, habitat, predation and/or resource availability. There has been no evidence for population bottlenecks in the species. Males tend to have pedomorphic traits which include a shorter face, large orbits and an enlarged neurocranium. It is not certain how long ago and where this evolutionary change occurred.
Through molecular analyses, it is indicated that P. kirkii is more closely related to the Udzungwa red colobus (P. gordonorum) compared to other red colobus species. This analysis has also placed the divergence of P. kirkii from its sister species P. godronorum at about 600,000 years ago, which actually allows for an older evolutionary age compared to the previous assumption that it had become its own species around the last glacial period. The species has been reclassified twice; it was previously in the genus Colobus, and more recently in the genus Procolobus and then the genus Piliocolobus.
An alternative common name is Kirk's red colobus after Sir John Kirk (1832–1922), the British Resident of Zanzibar who first brought it to the attention of zoological science.
Physical description
This Old World monkey's coat ranges from dark red to black, accented with a black stripe along the shoulders and arms, and a pale underside. Its black face is crowned with long, white hair, and features a distinguishing pink mark on its lips and nose. Also, the Zanzibar red colobus has a long tail used only for balancing—it is not prehensile. Females usually outnumber the males in their groups. The species has a notably small cranium and rotund body shape, with males potentially reaching over and females, . In adults, highly differentiated facial features help them to distinguish each other in a group.
The word "colobus" comes from Greek ekolobóse, meaning "he cut short", and is so named because of the significant reduction in size, or complete lack of an opposable thumb in comparison to other primates. To make up for this, they have four long digits that align to form a strong hook, allowing them to easily grasp branches and climb.
Habitat
The Zanzibar red colobus is found in three forests of the Zanzibar archipelago. It displays a wide habit tolerance, but it is mainly an arboreal species and prefers drier areas over wet ones. Its habitats include coastal thickets and coastal rag scrub, but it can also be found in agricultural areas and in mangrove swamps; the latter provides food year-round. The largest and most significant area of protection and habitat for the monkey is in Jozani National Park, which provides of land reserve. It is located on the main island and the populations here have been greatly studied in regards to both their ecology and behavior. Even so, many groups have been found in shambas (Swahili for "farmland") in close proximity to the park. In these shambas adjacent to the park, higher densities of the red colobus have been reported living here in more cohesive groups, compared to inside the park reserve. It is one of the few species that do not eat ripe fruits; it has a sacculated stomach with four chambers specific for breaking down plant materials, however it cannot digest the sugars contained in mature fruits. Because the monkey feeds on young leaves (though not limited to them), there are instances where it consumes charcoal, which is believed to aid their digestion of the toxins (possibly phenolic compounds) found in the young leaves of the Indian almond tree and mango tree. It has been noted, however, that not all populations on the islands carry out the behavior, but that it is rather mostly done by those who consume more perennial and exotic foliage.
In the dry season, one of the staple foods, Indian almond tree, as previously mentioned, drops its leaves and can cause the monkey to go beyond park boundaries in order to extend its feeding range. This puts the already endangered colobine at more risk. The birth rates themselves, however, are actually decreased in comparison to mainland colobus monkeys and interbirth intervals are longer as well.
Various attempts have been made for conservation of the species. One project was with the World Wildlife Fund, specifically in Menai Bay which is located just west of Uzi Island.
The African Convention has played a role in the conservation of the animal by categorizing it as 'Class A.'</blockquote>
It has been suggested that an important way to promote conservation of the monkey is to simply spread awareness about it – that it is not a harmful animal and that it can actually be good for the region's economy because it draws tourism. This has been the case on the island of Unguja (Zanzibar).